Heavy metal content of selected raw medicinal plant materials: implication for patient health

Abstract

The safety and quality of herbal medicines has become increasingly important for health authorities, scientific community and the public alike. Thus this study was aimed at determining the amount of heavy metals in selected raw traditional medicines. Heavy metal concentrations in these raw herbal drugs were found to be in the range of, 0.23-19.01 for Pb, 0.120.39 for Cu, 0.25-1.30 for Zn, 0.01-0.14 for Ni,1.41-30.84 for Fe and 0.01-0.46 mg kg-1for As. Heavy metal content that were found above permissible limits were: 19.01 for U. kirkiana bark and roots (Pb), U. kirkiana bark (12. 25 ± 0,01), roots (12.11 ± 0. 00) and O. americanum leaves (33.61.±0.07) and roots (30.84 ± 0.02) for iron. Significant difference was only noticed for each heavy metal among raw herbal drugs sampled from twenty one places for C. imberbe leaves and L. discolor roots (Pb) (ANOVA followed by least significant test at p = 0.05). Generally most of the drugs that are being used by people in Mashonaland central province were found to be toxic and unsafe for human consumption due to elevated levels of heavy metals especially Cu, Fe, As and Pb. It is suggested that pharmacovigilance must always be done to improve the quality, safety, and efficacy of herbal drugs. Every person dealing with plant medicine should be sensitized on how to maintain efficacy, quality and safety of such medicines.